Leaf
miner: Oviposition in the very leaf tip. From there a very deep upper surface
blotch extends downwards. The blotch, that is very transparent,
can occupy a large part of the leaf. Mostly the entire width of
the leaf is mined out, but the broad leaves of the Goat Willow are
mined at one side of the midrib only. Pupation within the mine in
a large, transparent, discoidal cocoon (Bladmineerders van Europa).